Delivery Unit

ABSTRACT

A delivery unit for delivering fuel from a tank to the internal combustion engine of a motor vehicle comprises an impeller revolving in a pump chamber. The impeller, on at least one end face, has a ring of blades spaced apart from one another in the circumferential direction. The impeller blades each have one front side leading in the direction of revolution and one rear side trailing in the direction of revolution. The blades have at least one triangular, oval, circular, or circular-sector-shaped oblique face on the radially outward front side and/or the radially inward rear side in the region of the end faces, which advantageously enlarges an inflow and outflow face formed between the blades and discharging into the chamber, thereby increasing efficiency of the delivery unit.

The invention is based on a delivery unit as generically defined by the preamble to the main claim. A delivery unit is already known from U.S. Pat. No. 6,454,520 B1, having an impeller, which revolves in a pump chamber and which on at least one end face has a ring of blades, spaced apart from one another in the circumferential direction, which each have one front side leading in the direction of revolution and one rear side trailing in the direction of revolution and cooperate with an annular delivery conduit of the pump chamber. One blade chamber is formed between each of the individual blades. The fluid leaves the delivery conduit, radially inward with regard to an axis of rotation of the impeller, to enter the blade chambers and emerges from these chambers radially outward again into the delivery conduit. To improve the inflow and outflow into and out of the chambers, the blades, on their edge formed by a face end and the rear side, have a chamfer extending continuously from radially inward to radially outward.

It is disadvantageous that the edge formed by the face end and the front side does not have a chamfer. As a result, on outflow from the blade chamber, the flow experiences an increased flow resistance. If the edge formed by the face end and the front side did have a continuously extending chamfer, as the edge formed by the face end and the rear side does, then the wall thickness of the blades, measured in the direction of revolution, would have to be increased, which would in turn increase the resistance to the flow.

ADVANTAGES OF THE INVENTION

The delivery unit according to the invention having the definitive characteristics of the main claim has the advantage over the prior art that in a simple way, an improvement in the efficiency of the delivery unit is attained by reducing the flow resistance, in that at least one blade, radially outward on the front side and/or radially inward on the rear side in the region of the face ends, has at least one triangular, oval, circular, or circular-sector-shaped oblique face. In this way, more surface area is provided for the flow on the radially inner and radially outer ends of the blades, so that the flow can enter the blade chambers at a predetermined inflow angle and leave the blade chambers at a predetermined outflow angle.

By the provisions recited in the dependent claims, advantageous refinements of and improvements to the delivery unit defined by the main claim are possible.

It is especially advantageous if the oblique face of the blades is formed such that an imaginary oblique section from one end of the blades extends with decreasing depth in the radial direction of the other end of the blades, since this embodiment is especially easy to produce by injection molding.

It is also advantageous that the oblique face has edges, which define the oblique face and which extend in the other direction from the adjoining edges of the adjacent faces.

It is highly advantageous that the oblique face enlarges an inflow and outflow face, formed between the blades and discharging into the chamber, since in this way the efficiency of the delivery unit is increased.

Advantageously, the oblique face is embodied as either plane or curved.

It is also advantageous if the radial length of the oblique face with regard to a pump axis is less than the radial length of the blades.

DRAWINGS

Exemplary embodiments of the invention are shown in simplified form in the drawings and described in further detail in the ensuing description.

FIG. 1 in section shows a view of a delivery unit;

FIG. 2 shows an impeller of this delivery unit;

FIG. 3 shows a blade according to the invention in a first exemplary embodiment;

FIG. 4 is a three-dimensional view of a blade of FIG. 3 with triangular oblique faces;

FIG. 5 is a three-dimensional view of a blade of FIG. 3 with circular-sector-shaped oblique faces;

FIG. 6 is a three-dimensional view of a blade of FIG. 3 with oval or circular oblique faces;

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 3;

FIG. 8 shows a blade of the invention in a second exemplary embodiment;

FIG. 9 is a sectional view taken along the line IX-IX in FIG. 8; and

FIG. 10 is a three-dimensional view of a blade of FIG. 8 with triangular oblique faces.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1 shows a delivery unit in which an embodiment of the blades in accordance with the invention can be employed.

The delivery unit of the invention serves to deliver a fluid, such as fuel, from a tank, for instance via a pressure line to an internal combustion engine.

The delivery unit embodied according to the invention has a pump housing 1, which has a pump part 2 and a motor part 3.

The delivery unit of the invention is a flow pump, for instance a peripheral pump or a side-channel pump.

The pump part 2 has a pump chamber 4, in which an impeller 5 revolves rotationally about a rotationally symmetrical pump axis 8. The impeller 5 is driven by an actuator 9, provided in the motor part 3, via a drive shaft 10. The actuator 8 is for instance an electric motor and is disposed in a motor compartment 7 of the motor part 3.

A region upstream of the pump chamber 4 will be called the intake side of the unit, and a region downstream of the pump chamber 4 will be called the compression side of the unit.

The pump chamber 4 has a pump chamber inlet 11 and a pump chamber outlet 12. The pump chamber 4 is defined by two end walls diametrically opposite one another in the direction of the pump axis 8, specifically a first end wall 15 and a second end wall 16, and by an annular wall 17 in the radial direction relative to the pump axis 8; the pump chamber inlet 11 is disposed in the first wall 15, and the pump chamber outlet 12 is disposed in the second end wall 16.

The impeller 5, for instance on both end faces 20.1, 20.2, has a ring of blades 5.1 spaced apart from one another in the circumferential direction. Between the blades 5.1, chambers 5.2 are formed. For instance, the blades 5.1 and the chamber 5.2 of the first end face 20.1 of the impeller 5 are provided mirror-symmetrically on the second end face 20.2. The respective diametrically opposed chambers 5.2 of the two end faces 20.1, 20.2 of the impeller communicate with one another for instance via a connecting opening 26. Radially outward, the chambers 5.2 are for instance closed by the provision of an encompassing ring 5.3 on the radially outer ends of the blades 5.1.

Annular delivery conduits 14, which are disposed in the radial region of the blades 5.1, are provided in the end walls 15, 16.

The first end wall 15 is for instance part of a suction cap 18, and the second wall 16 and the annular wall 7 are for instance part of a pressure cap 19. In the suction cap 18, an inlet conduit 22 is provided, which discharges via the pump chamber inlet 11 into the pump chamber 4, and the pump chamber 4 communicates fluidically with motor compartment 7 via the pump chamber outlet 12 and an outlet conduit 23 that is provided in the pressure cap 19.

The pressure cap 19 has a through opening 24. The drive shaft 10, mechanically coupled to the actuator 9, protrudes from the motor compartment 7 through the through opening 24 in the pressure cap 19 into the pump chamber 4.

The axial width of the pump chamber 4 is greater than the axial width of the impeller 5, so that there is axial gap 20 approximately 10 to 30 micrometers in width between the impeller 5 and the end walls 15, 16. The difference between the width of the pump chamber 4 and the width of the impeller 5 is defined as the total axial gap.

The impeller 5 is for instance slipped onto the drive shaft 10 that protrudes into the pump chamber 4; for this purpose, the impeller 5 has an impeller opening 25, into which the drive shaft 10 at least protrudes so as to be joined to the impeller by positive and/or nonpositive engagement. The impeller 5 is supported on the drive shaft for instance in such a way that it is axially movable between the first end wall 15 and the second end wall 16.

The delivery unit for instance aspirates fluid from a tank 32 via the inlet conduit 22 and the pump chamber inlet 11 into the pump chamber 4 and delivers it via the pump chamber outlet 12, the outlet conduit 23, the motor compartment 7 of the motor part of the pump housing 1, and a pressure line 33, for instance to an internal combustion engine 34. A check valve 35 is for instance provided in the pressure line 33 so as to maintain a predetermined pressure in the pressure line 33 after the delivery unit has been shut off.

FIG. 2 shows an impeller from the prior art, which is embodied according to the invention as described in the following FIGS. 3-9.

In the impeller of FIG. 2, the parts that remain the same or function the same as in the delivery unit of FIG. 1 are identified by the same reference numerals.

FIG. 3 shows a detail of an impeller embodied according to the invention, in a first exemplary embodiment with a blade according to the invention.

In the impeller of FIG. 3, the parts that remain the same or function the same as in the delivery unit of FIG. 1 and the impeller of FIG. 2 are identified by the same reference numerals.

Viewed in a direction of revolution 29 of the impeller 5, the blades 5.1 have a front side 30 and a rear side 31. Toward the end faces 20.1, 20.2 of the impeller 5, the blades 5.1 have a face end 32.

According to the invention, it is provided that at least one blade 5.1 has at least one oblique face 38, radially outward on the front side 30 and/or radially inward on the rear side 31, in the region of the face end 32.

The oblique face 38 is provided radially outward in the region of a front edge 30.1, formed by the front side 30 and the face end 32 of the blades 5.1, and/or radially inward in the region of a rear edge 31.1 formed by the rear side 31 and the face end 32 of the blades 5.1.

In a first exemplary embodiment, the oblique face 38 of the blades 5.1 is formed such that an imaginary oblique section from one end of the blades 5.1 extends, with decreasing depth T, in the radial direction of the other end of the blades 5.1. The imaginary oblique section at the front edge 30.1 and rear edge 31.1 of the blades 5.1 extends over only a portion of the length of the front edge 30.1 and rear edge 31.1, respectively, so that the radial length of the oblique face 38 with regard to the pump axis 8 is less than the radial length of the blades 5.1.

The oblique face 38 is a portion of the surface of the front side 30 and the rear side 31.

The oblique face 38 has edges 39, which define the oblique face 38 and which extend in a different direction (FIG. 4) from the adjoining edges of the adjacent faces 30, 31, 32. As a result, the oblique face 38 has an inclination relative to the front side 30 and the rear side 31. The oblique face 38 thus extends obliquely relative to the front side 30, the rear side 31, and the face end 32 of the blades 5.1 and thus in a different direction in space than the face of the front side 30, of the rear side 31, and of the face end 32 of the blades 5.1.

The oblique face 38 is embodied such that the flow resistance upon inflow and outflow enlarges an inflow and outflow face formed between the blades 5.1 and discharging into the chamber 5.2.

According to the invention, the oblique face 38 is embodied for instance in triangular form (FIG. 3, FIG. 4), in the form of a sector of a circle (FIG. 5), or in oval or circular form (FIG. 6), or the like. The oblique face 38 may be embodied as plane or curved.

FIG. 4 shows a blade embodied according to the invention, in accordance with the first exemplary embodiment, having a triangular oblique face.

In the blade of FIG. 4, the parts that remain the same or function the same as in the delivery unit of FIG. 1 and the impeller of FIGS. 2 and 3 are identified by the same reference numerals.

Looking in the radial direction with respect to the pump axis 8, the blades 5.1 are embodied for instance as V-shaped or arrowhead-shaped. The two legs of the V-shaped blades 5.1 are positioned obliquely relative to the pump axis 8. On the radially inner end of the rear edge 31.1 and on the radially outer end of the front edge 30.1, the blades 5.1 for instance have triangular oblique faces 38. The triangular oblique faces 38 are formed by three edges 39. For instance, the blades 5.1 have oblique faces 38 according to the invention toward both end faces 20.1, 20.2 of the impeller 5.

FIG. 5 shows a blade embodied according to the invention in accordance with the first exemplary embodiment, with an oblique face in the form of a sector of a circle.

In the blade of FIG. 5, the pans that remain the same or function the same as in the delivery unit of FIG. 1 and the impeller of FIG. 2 through FIG. 4 are identified by the same reference numerals.

FIG. 6 shows a blade embodied according to the invention in accordance with the first exemplary embodiment, having an oval or circular oblique face.

In the blade of FIG. 6, the parts that remain the same or function the same as in the delivery unit of FIG. 1 and the impeller of FIG. 2 through FIG. 5 are identified by the same reference numerals.

FIG. 7 shows a sectional view of the impeller taken along the line VII-VII in FIG. 3 in accordance with the first exemplary embodiment.

In the impeller of FIG. 7, the parts that remain the same or function the same as in the previous drawings are identified by the same reference numerals.

The fluid flows from the delivery conduits 14 radially inward into the chambers 5.2 of the impeller 5 at an inflow angle E and radially outward at an outflow angle A from the chambers 5.2 into the delivery conduits 14. The inflow angle E and the outflow angle A are embodied differently by the oblique faces 38; the inflow angle E is larger than the outflow angle A.

In the pump chamber 4 of the delivery unit, a spiral circulatory flow ensues, which upon inflow into the chambers 5.2 and upon outflow from the chambers 5.2 experiences a flow resistance. By the provision of the oblique faces 38, a greater inflow and outflow surface area is made available, and the flow resistance is thus reduced markedly. The oblique faces 38 enlarge the inflow angle E and the outflow angle A compared to the prior art. Because of the enlargement of the outflow angle A, local underpressure zones at the blade edges 30.1, 31.1 are avoided or at least are reduced in size. In this way, the delivery of fuel at high temperature (so-called hot-gasoline delivery) is improved.

FIG. 8 shows a detail of an impeller of the invention in a second exemplary embodiment.

In the impeller of FIG. 8, the parts that remain the same or function the same as in the previous drawings are identified by the same reference numerals.

The blades 5.1 in the second exemplary embodiment are, as in the first exemplary embodiment, shaped like a V or an arrowhead. The blades 5.1 in the second exemplary embodiment differ from the blades of the first exemplary embodiment in that radially outward they have a portion 5.4 that trails in the direction of revolution 29 and radially inward they have a portion 5.5 that leads in the direction of revolution 29. The trailing portion 5.4 and the leading portion 5.5 are for instance angled relative to a middle portion 5.6 that is provided between the portions 5.4 and 5.5. As a result of this angled embodiment of the blades 5.1, it is attained that the outflow angle A (FIG. 9) is enlarged still further, and as a result underpressure zones at the blade edges 30.1, 31.1 are avoided or at least reduced in size, which further improves the delivery of hot gasoline. Moreover, an improvement in the inflow and outflow from the pump chamber 5.2 is attained, so that the flow losses are reduced.

The blades 5.1 in the second exemplary embodiment also have at least one oblique face 38 radially outward on the front side 30 and/or radially inward on the rear side 31 in the region of the face end 32, and these oblique faces are embodied as described for the first exemplary embodiment.

FIG. 9 shows a sectional view of the impeller taken along the line IX-IX in FIG. 8 in accordance with the second exemplary embodiment.

FIG. 9 shows a detail of an impeller of the invention in a second exemplary embodiment.

The angling of the blades 5.1 in the portions 5.4, 5.5 extends over the entire width B of the impeller 5.

FIG. 10 shows a three-dimensional view of a blade with triangular oblique faces in accordance with the second exemplary embodiment.

FIG. 9 shows a detail of an impeller of the invention in a second exemplary embodiment. 

1-7. (canceled)
 8. A delivery unit for delivering fuel from a tank to an internal combustion engine of a motor vehicle, comprising: an impeller revolving in a pump chamber; a ring of blades spaced apart from one another in the circumferential direction on at least one end face of the impeller; each blade of the impeller having one front side leading in a direction of revolution and one rear side trailing in the direction of revolution; and at least one oblique face, disposed radially outward on a front side and/or radially inward on a rear side in a region of the end faces.
 9. The delivery unit according to claim 8, wherein the oblique face of the blades is formed such that an imaginary oblique section from one end of the blades extends with decreasing depth (T) in the radial direction of an opposite end of the blades.
 10. The delivery unit according to claim 8, wherein the oblique face has edges, disposed on the oblique face and which extend in an opposite direction from adjoining edges of adjacent faces.
 11. The delivery unit according to claim 8, wherein the oblique face is embodied such that it enlarges an inflow and outflow face that is formed between the blades and opens out into a chamber disposed between the blades.
 12. The delivery unit according to claim 8, wherein the oblique face is curved or plane.
 13. The delivery unit according to claim 8, wherein the oblique face is a portion of triangular, oval, circular, or circular-sector-shaped to the surface of the front side and rear side.
 14. The delivery unit according to claim 8, wherein a radial length of the oblique face with regard to a pump axis is less than a radial length of the blades.
 15. The delivery unit according to claim 8, wherein the oblique face is triangular, oval, circular, or circular-sector-shaped.
 16. The delivery unit according to claim 9, wherein the oblique face is triangular, oval, circular, or circular-sector-shaped.
 17. The delivery unit according to claim 10, wherein the oblique face is triangular, oval, circular, or circular-sector-shaped.
 18. The delivery unit according to claim 11, wherein the oblique face is triangular, oval, circular, or circular-sector-shaped.
 19. The delivery unit according to claim 12, wherein the oblique face is triangular, oval, circular, or circular-sector-shaped.
 20. The delivery unit according to claim 13, wherein the oblique face is triangular, oval, circular, or circular-sector-shaped.
 21. The delivery unit according to claim 14, wherein the oblique face is triangular, oval, circular, or circular-sector-shaped. 